Elastic constants of silicon materials calculated as a function of temperature using a parametrization of the second-generation reactive empirical bond-order potential

Abstract

A parametrization for silicon is presented that is based on the second-generation reactive empirical bond-order (REBO) formalism [Brenner, Shenderova, Harrison, Stuart, Ni, and Sinnott J. Phys.: Condens. Matter 14, 783 (2002)]. Because it shares the same analytic form as Brenner’s second-generation REBO, this new potential is a step toward a single potential that can model many atom systems that contain C, Si, and H, where bond breaking and bond making are important. The widespread use of Brenner’s REBO potential, its ability to model both zero-Kelvin elastic constants of diamond and the temperature dependence of the elastic constants, and the existence of parameters for many atom types were the motivating factors for obtaining this parametrization for Si. While Si-C-H classical bond-order potentials do exist, they are based on Brenner’s original formalism. This new parametrization is validated by examining the structure and stability of a large number of crystalline silicon structures, by examining the relaxation energies of point defects, the energies of silicon surfaces, the effects of adatoms on surface energies, and the structures of both liquid silicon and amorphous silicon. Finally, the elastic constants of diamond-cubic and amorphous silicon between 0 and $1100\mathrm{K}$ are calculated with this new parametrization and compared to values calculated using a previously published potential.